1. Technical Field
The present invention relates to display apparatus and methods of operation therefor. In particular, but not exclusively, the present invention relates to display apparatus comprising an orientation sensitive user interface mechanism.
2. Discussion of Related Art
Various types of display apparatus are well known, for example cathode ray tubes, liquid crystal displays and plasma displays, such as may be used for television or visual display units for computer systems, or hand or palm held computers. Many types of display apparatus are associated with or include orientation sensitive interface mechanisms. For example, user interface mechanisms such as keyboards or keypads, microphones, loudspeakers and the displayed image itself.
Taking loudspeakers as an example, typically, television displays, and increasingly VDU displays, have integral speakers which are configured to provide stereophonic sound reproduction for a viewer. Such displays may be used as mobile display appliances or apparatus to provide highly versatile display media for conferences, seminars, advertising and information points such as tourist information, and for personal mobile computing devices, for example. The image displayed on the display can be dynamic and may even be alterable by a user inputting control signals in response to a menu display, for example. Audio feedback and information may be conveyed to the viewer via the speakers. Displays may be entirely portable or may be movable between different locations although removably fixed into place during operation. Furthermore, depending upon the nature of the image to be displayed, the display apparatus may be configured in a landscape or portrait orientation. That is to say, in a landscape orientation the display axis having the greatest dimension is substantially horizontal, whilst in the portrait orientation the axis having greatest dimension is substantially vertical.
In stereophonic reproduction, two loudspeakers, conventionally referred to as left and right speakers as viewed from an observer, and labelled 2 and 4 respectively in FIG. 1, are each fed with a respective audio signal. The respective audio signals are such that when the speakers 2,4 are appropriately disposed along a stereo baseline 6 with respect to each other and to a listener 8, the listener experiences an audio image representative of the source from which the audio signal was created. That is to say, the listener experiences a spatial audio image. In order for the stereophonic effect to be reproduced accurately, the speakers 2,4 and listener 8 should be disposed relative to each other such that the stereo baseline 6 subtends an angle of 60° with respect to the listener 8. In other words, the speakers 2, 4 and listener 8 should preferably form the vertices of an equilateral triangle.
Referring now to FIGS. 2 and 3, displays in both the landscape orientation, FIGS. 2a and 3a, and portrait orientation, FIGS. 2b and 3b, are illustrated. FIG. 2 illustrates a display apparatus 20 having a display 22. The display apparatus 20 also comprises four speakers 24 respectively disposed at each corner of the display apparatus.
Referring now to FIG. 3, further display apparatus 20 is illustrated, having a display 22 and four speakers 24. However, in the apparatus illustrated in FIG. 3, the speakers 24 are each disposed at a halfway point along respective sides of the apparatus 20.
FIGS. 2a and 3a illustrate the display apparatus 20 configured in landscape orientation, and FIGS. 2b and 3b in a portrait orientation. The landscape orientation is defined as the longest dimension of the display 22 being horizontal relative to a viewer, and the portrait orientation is defined as the longest dimension of the display 22 being vertical relative to a viewer. The terms “horizontal” and “vertical” are used herein with reference to a viewer and are to be interpreted within that context and should not be limited to any strict geometrical meaning which the respective words might have. Furthermore, the terms “viewer” and “listener” are used interchangeably and are not limiting on the scope of the invention or appended claims.
The provision of four speakers for the display apparatus illustrated in FIGS. 2 and 3 is important with regard to the maintenance of a stereo base for both landscape and portrait orientations.
In a landscape orientation, the display mode of the display apparatus would generally also be landscape, and the display of FIG. 2a would typically produce stereo sound by utilising speakers 24a and 24b to provide the left channel speakers, and speakers 24c and 24d to provide right channel speakers, denoted in FIG. 2a by Lll and Llr, respectively, for the stereo base. In FIG. 3a, single speakers 24a and 24c provide the left and right speakers for the stereo base and are also denoted Lll and Llr, respectively. When the display apparatus 20 is in a portait orientation, with the display mode also in portrait mode, the respective speaker pairs forming the left channel speakers Lll and right channel speakers Llr for the landscape orientation are at the bottom and top of the display, respectively. Consequently, they are unsuitable for providing a tereo base to a viewer for the display being in a portrait orientation.
When the display apparatus is placed in a portrait orientation, as illustrated in FIG. 2b, the speakers providing the stereo base in the landscape orientation are now disposed at the top and bottom of the display apparatus. Consequently, it is necessary to switch operation of the speakers to speakers 24a and 24c (Lpl) and speakers 24b and 24d (Lpr) in order to provide the left and right channels, respectively, of the stereo base for the portrait orientation. Such switching is known in the prior art.
Referring now to FIG. 3a, speaker 24a provides the left channel speaker (Lll) and speaker 24c provides the right channel speaker (Llr) in the landscape orientation. FIG. 3b illustrates the display in portrait orientation with speaker 24d providing the left channel speaker (Lpl) and speaker 24b providing the right channel speaker (Lpr).
A drawback of the known display apparatus illustrated with reference to FIGS. 2 and 3 is that they require at least four speakers. In order to operate correctly, the speakers need to be of sufficient size and, consequently, any display apparatus must have a sufficiently large housing in order to incorporate and support the speakers. Thus, the display apparatus housing can become bulky and unattractive. This is a particular problem when the display apparatus is part of a mobile or portable device, for example a laptop or hand/palm held personal computer or display device, a personal digital assistant or a wireless telephone, since the provision of housing for bulky loudspeakers is inconsistent with the general desire to provide lightweight, low-volume, portable devices. An example of a multimedia portable wireless device is the Nokia™ Communicator™.